After saving the world, the Legends of Tomorrow now are charged with protecting time - the past, present, and future - itself. This responsibility will take them across history, bringing them up against a threat unlike humanity has ever known.

Dr. Nate Heywood (Nick Zano), an unconventional and charming historian, is thrust into the action. After making a shocking discovery, Nate seeks out Oliver Queen (guest star Stephen Amell) for help in finding the scattered Legends.

Once reunited, the Legends continue their new mission to protect the timeline from temporal aberrations - unusual changes to history that spawn potentially catastrophic consequences. Their first stop is 1942 to protect Albert Einstein from being kidnapped before the Nazis destroy New York City with a nuclear bomb.

Meanwhile, Ray (Brandon Routh) notices that Sara (Caity Lotz) has a mission of her own, which leads them both to face her nemesis, Damien Darhk (guest star Neal McDonough). Victor Garber, Arthur Darvill, Dominic Purcell and Franz Drameh also star.